1. Technical Field
One or more embodiments of the invention relate to apparatus and methods for hydrocarbon extraction from a hydrocarbon-containing material. More particularly, various embodiments of the invention relate to extracting hydrocarbon from a hydrocarbon-containing material with an extractant.
2. Description of Related Art
Oil sands (a.k.a., tar sands) are a type of hydrocarbon deposit that typically contain bitumen, which is an extra heavy type of oil or petroleum. Generally, oil sands are naturally occurring mixtures of sand, clay, water, and bitumen. Given the dense and viscous nature of bitumen, it cannot be pumped from an oil sands deposit using conventional petroleum extraction methods. Thus, various techniques have been developed to recover bitumen from oil sands deposits, such as strip mining, open pit mining, or extraction methods involving lowering the viscosity of the bitumen, such as by heating or addition of solvents.
Much of the world's petroleum reserves are in the form of oil sands. In fact, it is estimated that as much as two-thirds of the world's petroleum reserves are located in oil sands deposits, which have the combined potential to produce more than three trillion barrels of petroleum. Oil sands deposits are found throughout the world, with the largest deposits found in Canada, Venezuela, and the Middle East. In the Unites States, oil sands are generally found in the western states, primarily in Colorado, Wyoming, and Utah. Estimated U.S. bitumen reserves total near 100 billion barrels.
Historically, the relatively low cost of petroleum has made bitumen extraction unattractive for economic reasons, given the much higher cost of obtaining and upgrading bitumen compared to conventional petroleum. In recent years, however, the increased cost per barrel of oil has made bitumen extraction a profitable venture. Typically, oil sands deposits near the surface are recovered by open pit mining techniques. Large powered shovels load oil sands ore into trucks for transport to an extraction plant, where hot water separates the bitumen from the oil sands ore in large agitated separation vessels. Here, the bitumen floats to the surface and is skimmed off for further processing and refinement. These systems require large quantities of water and have an increased potential for water pollution. In arid regions, bitumen recovery by these methods places additional strain on scarce water resources. Accordingly, improved bitumen recovery methods are desired that reduce or eliminate water usage and/or pollution.